In recent years, the need for cleaner work space has grown in locations such as manufacturing locations for highly functional precision equipment such as optical parts, including digital cameras, cell phones, semiconductor manufacturing including IC chip manufacturing, production of liquid crystal parts such as flat-panel displays, and manufacturing, inspection and research locations that handle chemicals, pharmaceuticals and/or the like due to the large effect the mixing of dust, environmental microbes and/or the like has on product quality and research results.
In response to these needs, methods that locally clean only a portion of the work space that needs to be cleaned are typical, and a clean bench method is a representative clean zone forming technology. This clean bench method has a work opening only in front of the work table, and other surfaces are enclosed, including the ceiling, in order to maintain cleanliness. A clean air blowing opening is positioned inside this enclosure, and a worker does the work by inserting his hands through the work opening in front of him. Clean benches with various functions appended have been proposed on this basic structure. Examples of commonly known publications proposing such a clean bench include JP2001-141273A, JP2005-48970A and JP2006-162174A.
Clean benches known from before had difficulty in operability in that many had small work openings, making assembly work on precision equipment difficult. In addition, in assembly work on production lines such that products and parts are manufactured while being transported by a conveyor and/or the like, the clean bench method could not be adopted on production lines because the indispensable enclosure became a hindrance.
In this case, a clean room method in which an entire work room including the production line is cleaned is used, but this approach causes facilities to become large-scale, creating difficulties in securing installation space needed for larger systems and causing the expense of the system itself as well as installation costs to rise. Moreover, operating costs, such as electricity bills and replacement filter maintenance expenses needed to maintain high cleanliness in this broad space, become enormous.
Besides these, another method for manufacturing production parts and/or the like without contamination is a mini environment method that partially controls contamination inside a barrier by isolating the worker, but while this can create a highly clean zone, it is necessary to completely isolate the worker and the production parts and/or the like, making it impossible for the worker to directly do the work.
The present inventor and others proposed a local air cleaning apparatus in which a pair of push hoods are arranged facing each other so that the two airflows collide, as a local air cleaning apparatus that has excellent operability and can provide an excellent clean zone without restricting the purpose of an operation (JP2008-275266A).
This apparatus can form a clean air space without using a wall or enclosure, with boundary surfaces parallel to the airflow direction formed between the air blowing surfaces of the pair of facing push hoods all being in an open state, and thus has excellent operability because there is no hindrance to the operation by an enclosure and/or the like. In addition, because there is no enclosure, it is possible to use a production line accompanying transport of the parts. However, in the case of this apparatus it is necessary to have the blowing opening surfaces face each other, so in some cases it is difficult to accomplish work without the worker himself entering the formed airflow on a production line accompanying parts transport, and in such a case, a clean zone cannot be formed because the worker obstructs the air blowing surface of the push hoods. In addition, in locations having difficult-to-move obstacles such as pillars, manufacturing equipment and/or the like in the apparatus installation area, and in confined work rooms and/or the like, installation with a positional relationship such that the blowing opening surfaces face each other is impossible, creating the problem that even if the equipment can be installed, unnecessary space is used.